Flickering spot light shadows in GLSL
You need set up only one sun lamp.


(Asuming all objects are deselect)RigthMouseButton to select the sun lamp and while pressing Shit + RigthMouseButton select your player:

While both selected press Ctrl + P and select Vertex:





select, deselect all pressing A.
Select the sun lamp RigthMouseButton.
in property > data, active the shadow and show shadow check box.





In Quality you can edit the shadow size (higher value more impact)
In Quality you can edit the 'Bias' value, set to 0.1 and then go up to see what happens :P.
In Clipping the clip end value define the distance, beyond which objects will no generate shadows





In Clipping the frustum size value define the box size


Note HIGHER VALUES MAY HAVE PERFORMACE IMPACT

EDIT

You will notice bad light:



Then add a Hemi lamp and point it oposite to the sun lamp




ANSWER ANSWER!

The problem is with the camera.

I have reproduced the problem in 2 ways.


Positioning the camera closer or inside of an object with camera physics static
Positioning the camera inside of an object with camera physics no collision


Also found that your camera was tiny and the cylinder(character) too.
take a look to the blender manual> render>camera

To solve it:

1.Delete the camera and add a new camera (and dont scale it)

2.Move the camera To Position (dont put it inside of an object.) Make sure that the camera physics are no collision.


Yo can change the size of the camera:




And then you can parent the camera to object, and the sun to the  vertex object (better with vertex make parent in edition mode).